2009/04/22 by Robert Brandenberger · 1 citation
Physics and Astronomy · #hep-th #astro-ph.CO #gr-qc #hep-ph
paper · pdf · doi:10.1103/physrevd.80.043516
6 pages, 1 figure, a couple of minor wording changes
arxiv created 2009/04/22 · arxiv updated 2013/05/29
Horava-Lifshitz gravity, a recent proposal for a UV-complete renormalizable gravity theory, may lead to a bouncing cosmology. In this note we argue that Horava-Lifshitz cosmology may yield a concrete realization of the matter bounce scenario, and thus give rise to an alternative to inflation for producing a scale-invariant spectrum of cosmological perturbations. In this scenario, quantum vacuum fluctuations exit the Hubble radius in the pre-bounce phase and the spectrum is transformed into a scale-invariant one on super-Hubble scales before the bounce because the long wavelength modes undergo squeezing of their wave-functions for a longer period of time than shorter wavelength modes. The scale-invariance of the spectrum of curvature fluctuations is preserved during and after the bounce. A distinctive prediction of this scenario is the amplitude and shape of the bispectrum.